Industrial Mechanic (Millwright) exam: Shaft alignment

Key points

• Offset (parallel) misalignment: centrelines are parallel but not in line.
• Angular misalignment: centrelines meet at an angle.
• Check and correct soft foot before aligning.
• Dial readings are TIR; the actual offset is half the reading.
• Allow for thermal growth when machines run hot.

Study tip

Do vertical moves (shims) before horizontal moves.

Try these

1. What should be corrected before alignment?

   1. Thermal growth
   2. Soft foot
   3. Coupling gap
   4. Belt tension
   Show answer

   B. Soft foot Soft foot makes readings unreliable.

2. A rim reading of 0.020 in TIR means an offset of:

   1. 0.005 in
   2. 0.010 in
   3. 0.020 in
   4. 0.040 in
   Show answer

   B. 0.010 in Half the TIR.

3. Shimming corrects misalignment in the:

   1. Horizontal plane
   2. Vertical plane
   3. Axial direction
   4. Rotational direction
   Show answer

   B. Vertical plane Shims move the machine up or down.

Keep going

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